libewf: Add bzip2 dependency for darwin

This is part of the series to support radare2 on darwin platforms.

When built from sources on darwin platforms, libewf fails as it depends
on lbz2.

pkgs/development/libraries/libewf/default.nix

@@ -1,4 +1,4 @@
-{ fetchurl, lib, stdenv, zlib, openssl, libuuid, pkg-config }:
+{ fetchurl, lib, stdenv, zlib, openssl, libuuid, pkg-config, bzip2 }:
 
 stdenv.mkDerivation rec {
   version = "20201230";
@@ -10,7 +10,8 @@ stdenv.mkDerivation rec {
   };
 
   nativeBuildInputs = [ pkg-config ];
-  buildInputs = [ zlib openssl libuuid ];
+  buildInputs = [ zlib openssl libuuid ]
+    ++ lib.optionals stdenv.isDarwin [ bzip2 ];
 
   meta = {
     description = "Library for support of the Expert Witness Compression Format";